KOI8-R to UTF-8 - Russian Unix Text Converter

Convert KOI8-R encoded Russian text to UTF-8. Essential for legacy Unix/Linux email archives, FTP transfers, and Soviet-era system data migration.

Input (KOI8-R)

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TXT, LOG, CSV from Unix/Linux systems

Or paste text directly:

Output (UTF-8)

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Frequently Asked Questions

KOI8-R (Kod Obmena Informatsiey, 8-bit) is an 8-bit character encoding designed for Russian Cyrillic text. Developed in the Soviet Union in 1974, it became the standard for Russian text on Unix and Linux systems throughout the 1990s and early 2000s.

KOI8-R was created during the Soviet era as an extension of ASCII to support Cyrillic characters. It cleverly maps Russian letters so that if the 8th bit is stripped (common in 7-bit transmission), the result approximates transliterated Latin text. This made it popular for email and newsgroups before Unicode became standard.

While both encode Russian Cyrillic, they use completely different byte values for the same letters. KOI8-R was the Unix/Linux standard, while Windows-1251 dominated Windows systems. Text encoded in one will appear as gibberish if decoded with the other. KOI8-R has the unique 8-bit stripping fallback feature that Windows-1251 lacks.

Modern systems use UTF-8 as the universal standard. Converting KOI8-R to UTF-8 allows legacy Russian text from old Unix systems, email archives, FTP transfers, and databases to display correctly on contemporary platforms and integrate with modern applications.

KOI8-R was designed so that if the high bit (8th bit) of each byte is removed—which happened in early 7-bit email systems—Russian text becomes readable transliterated Latin text. For example, 'Привет' becomes 'Privet'. This made it robust for early internet communication where 8-bit data might be corrupted.

Both. You can paste text directly into the converter, or upload files (TXT, CSV, LOG, etc.) encoded in KOI8-R. The tool reads the raw bytes using the KOI8-R codec and outputs properly decoded UTF-8 text that you can copy or download.

If Russian text displays as gibberish with characters like 'ëÅÒ×ÙÊ', it might be KOI8-R. Common sources include old Unix shell output, email from Russian .su domains in the 1990s, FTP log files from legacy servers, and exported database dumps from pre-2005 systems.

Mixed encoding in a single file is the most common problem—some parts might be Windows-1251 or UTF-8 already. Also, some characters outside the core Cyrillic set may not be defined in KOI8-R and will appear as replacement characters. Always preview the output before committing to ensure proper conversion.

In the 1990s and early 2000s, Russian email and Usenet newsgroups primarily used KOI8-R because most Russian internet infrastructure ran on Unix systems. Email servers, mailing lists, and discussion forums defaulted to KOI8-R. Converting these archives to UTF-8 is essential for modern email clients and search tools.

Currently, the tool processes one file at a time to ensure accuracy and avoid browser memory issues with large batches. For bulk conversion of many files, you can use the tool repeatedly or consider server-side batch conversion tools for very large archives.

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